This invention is directed generally to electromechanical devices and, more specifically, to an anti-twist insert for use in a switch-lock assembly of a circuit breaker.
Electrical devices, such as circuit breakers, are used in many residential, commercial, and industrial electric systems, being indispensable components of such systems in protecting against over-current conditions. A circuit breaker includes a switch that can be placed in at least two positions: an ON position and an OFF position. In the ON position the circuit breaker closes an electrical circuit, thus allowing the flow of current in the particular circuit. In the OFF position the circuit breaker opens the electrical circuit, thus interrupting the flow of current in the particular circuit.
Under certain circumstances, it is desirable to lock the switch in either the ON position or the OFF position. For example, if a person is servicing components of an electrical circuit it is highly desirable to ensure that the circuit breaker remains in the OFF position. Serious bodily injury, even death, may result if the circuit breaker is accidentally turned ON while the person is in contact with components of the electrical circuit. Similarly, to prevent trespassers from tampering with an electrical circuit, it may be desirable to lock a circuit breaker in the ON position. This would ensure that only an authorized person may manually interrupt the flow of current.
Although some switch-locking devices for circuit breakers are available, they are in general expensive, complex, or flimsy. For example, a switch-locking device comprises a support part, a locking part, and a spring clip. The spring clip has a middle section that is fixed in the locking part, two legs that are slidably-engaged in two slots of the support part, and two ends that are inserted into two holes of a circuit breaker. After the locking part is swung in a counterclockwise direction to fit over the support part, the circuit breaker can be locked by inserting a padlock into a ring of the support part. Although such a switch-locking device provides adequate support when subjected to a tensile force, i.e., when the device is being pulled, it is nevertheless too flimsy when it is subjected to compressive or rotational forces, i.e., when the device is being pushed or twisted. The weak protection that the device provides when being pushed or twisted is due in great part to the fact that the support comes only from the two legs of the spring clip. For example, the switch-locking device can be separated from the circuit breaker when it encounters a relatively low twisting force because the two legs are easily displaced from their respective holes. Regardless of whether the twisting motion is accidental or intentional, the twisting motion renders the switch-locking device highly unreliable.
Accordingly, there is a need for a simple component that would prevent the easy removal of the switch-locking device when a twisting force is applied. There is also a need for a simple component that would provide greater support when a compressive force is applied to the switch-locking device.
Briefly, in accordance with the foregoing, a switch-lock assembly, for securing a circuit breaker in one of a plurality of circuit breaker positions, includes a switch-lock attachment and an anti-twist insert. The switch-lock attachment includes a spring member adapted to engage a retaining area of the circuit breaker, a support member adapted to accommodate the spring member, and a locking member connected with the support member via the spring member. The insert includes a securing end adapted to engage a first area of the circuit breaker for limiting the movement of the insert relative to the circuit breaker, and an interface area adapted to engage the switch-lock attachment for limiting the movement of the switch-lock attachment relative to the insert.